Hepatitis B virus is the most thoroughly characterized pathogen of the hepatitis diseases. The hepatitis B virus is associated with a wide spectrum of liver disease, from a subclinical carrier state to accute hepatitis, chronic hepatitis, postnecrotic (posthepatitic) cirrhosis, and hepatocellular carcinoma. It also has a poorly understood association with several primary non-hepatic disorders including polyarteritis nodesa and other collagen vascular diseases, membraneous glomerulonephritis, essential mixed cryoglobulinemina and papular acrodermatitis of childhood. Hepatitis symptoms and signs vary from minor flu-like illnesses to fulminant, fatal liver failure.
Groups at risk for contracting hepatitis B virus include certain hospital and dentist staff (e.g., oncology, hemodialysis-transplantation, gastroenterology, intensive care units, diagnostic laboratories, and surgical units), staff in institutions for the mentally handicapped, patients receiving blood and blood products, drug addicts, male homosexuals, and the families of chronic carriers.
The infective "DANE" particle consists of an inner core plus an outer surface coat. The inner core contains DNA and DNA polymerase. The DNA replicates within the nuclei of infected hepatocytes. The core antigen (HBcAg) is associated with the viral inner core. It can be found in infected liver cells but is not detectable in serum except by special techniques which disrupt the DANE particle. The hepatitis B virus is present in the cytoplasm of parenchymal liver cells of individuals with hepatitis B and constitutes the infective virus. The core particle displays HBcAg. The core of this particle is found in the nucleus of parenchymal cells, but as it passes through the cytoplasm, it acquires a surface coat.
Antibody to the core antigen appears promptly in the blood of infected individuals and persists indefinitely. High titers of IgM anti-HBc is found in patients with accute disease and may be the only marker of accute hepatitis B in some situations.
Serological detection of anti-HBc is accepted diagnostic evidence of hepatitis B viral infection. Therefore, it is desirable to have substantial quantities of HBcAg for use as an immunogen in development of monoclonal and polyclonal antibodies to the HBcAg, for preparing vaccines, and for use in detection of the viral infection in patients.